HUYGENS MCD
TECHNOLEGY

What's the
MCD?

MCD stands for "MHz Class-D",
A new amplifier technology from John.Fu(Fumac) and Zhaolian.Fu. This New Class
D amplifier technology runs a very high sampling rate Frequency (from around
700KHz~2.6Mhz, at a fixed frequency). This technology enables us to produce
amplifiers of high power(up to 800w), Low THD(0.00x%), Low phase-shift, and a
Class A like sound all from a compact, cool running, environmentally friendly
design, perfect for a HiFi, AV system, active speaker or professional
amplifier.

MCD amplifiers feature two feedback paths (Figure 1), one to
produce the High Frequency oscillation frequency, the other for AF error
feedback, this AF feedback includes the output filter to ensure load
independent performance. By combining these two loops, you can create a system
with both outstanding technical and subjective performance.

AF Error Feelback , Low
THD
MCD has an AF error feedback from the speaker terminal , this
feedback can fix the large THD from the filter , so MCD can get a very low THD
also at very high power output. Figure 5: samples of THD in high power output .

THD spectrum analyzer of MCD-300 at 2W 6ohm,

THD=0.0035%(-87db) at 1k ,THD=0.0100%(-80db) at 7k ,THD=0.0112%(-79db) at
15k

THD spectrum analyzer of MCD-300 at 100W(rms) 6ohm,

THD=0.016%(-76db) at 100Hz ,THD=0.012%(-78db) at 1k ,THD=0.016%(-74.5db) at
7k

The
Higher The Sample Frequency , The More Detail
Previous Class D technology ran below 100KHz. This is not quick
enough for full-range (10Hz~20KHz) audio performance, and can only be consider
suitable for subwoofer (10Hz to 250Hz) applications.
More recently Class D
designers have been able to increase the switching frequency of their designs
to 200k~250k. These type of Class D amplifiers can produce close to full range
audio (about 10hz ~18KHz). Typically these designs had great bass but poor
treble. Still these amplifiers have found homes in AV systems, sub woofers, and
Mid Fi applications. Figure 2 show level error at different speed of damp.

Bringing us up to date, there are some very good designs that now run at
between 350¨C400KHz. These are the first designs that can reproduce the
accepted "full bandwidth" (10Hz~22kHz) with finesse . However, the phase shift
between bass and treble is to great to produce a fully cohesive sound. (Figure
3)..

High Frequency, Low Phase-shift, Low EMI
MCD runs at speeds of between 700KHz to 2.6MHz
(up to 6 times faster then the current state of the art), It has an extended
audio bandwidth from below 1Hz to beyond 60KHz with a simple filter (80KHz Low
Pass Filter), as the high switching speed makes this possible.
Looking at he
picture(Figure 3 and Figure 4), the MCD generates lower EMI, has less phase
shift and has a greater bandwidth than other D Class amplifiers. With a AF
error feedback, the phase shift can be zero.

Balance response

A Butterworth filter is inside
most of HIFI class-d amps, this is make the lowest EMI of damp, make it work
well with others.
Some old class-d amp have a 3V carrier frequency
output(about 280mW, like a ).Class-d amp running in 400k have 0.8V(about 20mW
to 4ohm, like the output power of wireless microphone) . Through the speaker
line, it will transmit to anywhere. MCD just have less than 0.1V(about 0.3mW )
carrier frequency output. It's very lower than the others.
A simple filter
can't make the balance with audio frequency flag , low phase shift and lowest
carrier frequency output, except the carrier frequency far away from the
audioband. But MCD can, because the very high frequency(700k~2.65MHz).(Figure 3
Figure 4 )

Active
loads
Speakers have different loads, a 4ohm speaker some times
between 2ohm to 8ohm, sometimes we use a same AMP to drive different speakers,
this is call active load character.
The simple filter of class-d amp
response like Figure 5 , we found that the treble will different in the
different load.
Figure 6 shows the active load character include 400k
class-d amp and MCD, we found that the MCD have a more flag response than the
400K class-d amp (13.7dB VS 7.5dB from 1ohm to 16ohm) . This is meaning MCD can
driver different load with a same-like response.
MCD with a very strong
current output, most types of MCD can driver 1ohm load.

15 Years Experience, offer
customs design
John.Fu and
ChaoLian.Fu are the designer of MCD . They have Experience working in RF design
and AF design for 15 years, Good at super high speed PCB design and Hi-FI audio
design. This make the MCD work in very high performance. We offer our designs
to other companies for Custom design all around the world.

--------------------------------------------------------
copy
right: john.fu zhaolian.fu 2006~2007
email: [email-masked]
(skype)
website: www.class-d.net